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IVF Embryo Grade Decoder

Your embryo report, translated. Understand what every letter and number means — in plain English, in seconds. Information only. Your embryologist is your medical team — we're just here to help you understand the words.

Sourced from Gardner (1999) & Istanbul ConsensusNo account neededNothing stored on servers15 languages

Advanced tools

Beyond single-grade lookup — real cycle-level workflows.

Cycle summary

Across 6 embryos: 2 strong, 1 good, 1 moderate, 1 lower, 1 early.

2× strong1× good1× moderate1× lower1× early

Grouped by morphology tier

Strong morphology (2)
Embryo 14AAEmbryo 35AAHatching
Good morphology (1)
Embryo 23BB
Moderate morphology (1)
Embryo 44BCMixed ICM/TE grades — worth discussing with your embryologist
Lower morphology (1)
Embryo 63CC
Early-stage (1)
Embryo 52BBVery early blastocyst

Grouping is morphology-only. It does not indicate which embryo to transfer. Your embryologist considers many factors beyond grade — including genetic testing, your medical history, and clinical context.

Single-grade decoder

Quickly decode a single grade with the full animated breakdown and embryo diagram.

Try an example:
Your grade never leaves your browser. This is a translation — not a diagnosis or prediction. For decisions about your treatment, talk to your fertility team.
Loading 3D embryo…

Drag the embryo to rotate in 3D. Hover a breakdown row to highlight that cell group.

Type a grade on the left to see a gentle, plain-language breakdown.

Try 4AA, 3BB, or 8-cell Grade 1

How it works

1

Enter the grade from your embryology report.

2

We decode every part in plain language.

3

Get questions to bring to your embryologist.

Supported grading systems

Gardner

Most common worldwide. Format: number + two letters (e.g. 4AA). Number = expansion (1-6); letters = ICM and TE quality (A-C).

SART

US consensus system. Uses words: Good / Fair / Poor for overall quality plus stage name.

Istanbul Consensus

International standard from ESHRE/ALPHA. Three-tier Good / Fair / Poor across every stage.

Day 3 Cleavage

Early-stage grading. Format: cell count + Grade 1-4 (e.g. 8-cell Grade 1). Sweet spot is 7-9 cells.

Compare up to 3 embryo grades

Paste multiple grades to see a side-by-side breakdown — useful when discussing options with your embryologist.

Embryo 1
Strong morphology

This is considered a high-quality blastocyst. Both cell groups — the one that becomes the baby and the one that becomes the placenta — show strong development. This does not guarantee pregnancy, but it is a strong morphological profile.

Expansion
4
Inner
A
Trophectoderm
A
Embryo 2
Good morphology

This is a good-quality blastocyst. Many healthy pregnancies come from embryos graded like this. It does not predict pregnancy, but the morphology is solid.

Expansion
3
Inner
B
Trophectoderm
B
Embryo 3

Glossary

Blastocyst
An embryo that has developed a fluid-filled cavity, usually on Day 5 or 6.
Blastocoel
The fluid-filled cavity inside a blastocyst.
ICM (Inner Cell Mass)
The cluster of cells inside the blastocyst that becomes the fetus.
Trophectoderm (TE)
The outer cell layer of a blastocyst that becomes the placenta.
Zona pellucida
The protective outer 'shell' of the egg and early embryo.
PGT-A
Preimplantation Genetic Testing for Aneuploidy — checks chromosome count.
Euploid
An embryo with the normal number of chromosomes (46).
Fragmentation
Small pieces of cellular debris between cells; lower is better.
Morula
A Day-4 embryo where cells have compacted into a solid ball.
Hatching
The process where the blastocyst breaks out of its outer shell.
Gardner system
The most widely used blastocyst grading system, from 1999.
Istanbul Consensus
International standard for embryo assessment (2011, 2025 update).
Vitrification
Ultra-fast freezing technique used for embryos.
Multinucleation
A cell with more than one nucleus — may indicate abnormality.
Pronuclei (PN)
The two nuclei visible in a fertilized egg before they fuse.

Frequently asked questions

Have more questions? Contact us

About this tool

We built this decoder because too many patients spend hours Googling letters and numbers after their embryology report arrives. You deserve a clear, calm translation — without waiting for your next clinic appointment.

What this tool does

Translates embryo grading terminology (Gardner, SART, Istanbul Consensus, Day-3 cleavage) into plain English. Based on published clinical guidelines.

What this tool doesn't do

  • Predict whether your embryo will implant
  • Predict pregnancy or live birth
  • Recommend which embryo to transfer
  • Replace your embryologist or fertility doctor

Why we keep this line clear

Embryo grades describe appearance on a specific day. They are one of many factors your clinical team weighs. Lower-grade embryos become healthy babies every day, and top-grade embryos sometimes don't implant. Your team has information we don't — your full medical picture, imaging, history, and experience.

Talk to your fertility team about your specific grades and what they mean for your treatment plan.

Sources: Gardner & Schoolcraft (1999); ALPHA/ESHRE Istanbul Consensus (2011, updated 2025); Racowsky et al. (2010); Cutting et al. BFS/ACE guidelines (2008).

Last updated: 2026-06-07

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